perl -pi -e 's/ (\d{4}-)?(2017)(?= Free Software)/
               " ".($1||"$2-").($2+1)/e' **/*(^/)
under zsh, reverting the ck-mparam and timings-mpfr.c files and
the mbench directory under "tools" (not distributed with MPFR).
Removed 2017 from the example in the doc/README.dev file.

[From SVN r12067 (trunk)]